BMW R90/6 by Untitled Motorcycles

You know you’re doing something right when you’re based in London and get a commission from a German enthusiast to build a BMW. The compliment was paid to Untitled Motorcycles and this is the result: a very classy 1975 BMW R90/6 custom.

Untitled built the machine for Antonius from Essen. And it was no easy task: the R90 would have to pass the strict German TÜV test to make it road-legal.

After years of riding modern Triumphs, Moto Guzzis and BMWs, Antonius, 51, hankered after an old two-valve boxer BMW. “While searching the internet I discovered Untitled Motorcycles by chance,” he says. “I was inspired by the look of the UM bikes: clearly classic BMWs, but with a modern soul.”

Within two weeks Antonius had found the right donor bike. “He trailered over an R90/6, along with an R75 tank,” recalls Untitled’s Adam Kay. Co-builders Rex Martin and Anita Chatelan started work straight away, with an engine overhaul and a thorough vapor blasting of the heads, barrels and engine cases.

Untitled also installed new stainless steel pushrods, big end shells and valves. The carbs were stripped and overhauled too, and the battery relocated closer to the engine. The bike was completely rewired and new cables were hand-cut and routed to the brakes, clutch and throttle.

The subframe is now 15cm shorter than stock, and houses the ignition switch and starter button. It also has a subtle kick-up in the rear loop, to clear the custom rear fender. The R75 tank—smaller than the original R90/6 item—was butted up to a newly-fabricated seat. A custom headlight now sits ahead of the new bars, and includes extra warning lights to accommodate the TÜV requirements. The blinkers and the rear number plate were also installed according to TÜV specifications.

The silver paint is a color from the current BMW catalog, and the frame and many ancillary parts were powdercoated. The rims have been fitted with new stainless spokes and nipples, and are shod with Dunlop K70 tires.

“I think I now have the bike I will never sell,” says Antonius. “It was a lot of fun to develop the R90/6 with Untitled, even if they were a little obstinate sometimes. A silver headlight! I am still thinking of painting it black.”

The next build from Untitled will debut at The Bike Shed Event on 18-19 May at Shoreditch Studios in London. If you’re lucky enough to make it to the show, keep an eye out for it. If not, stay tuned—we’ll reveal it online here at the same time.